1. Field of the Invention
The present invention relates to a rotary electric machine having an engine cooling water pump and, more particularly, relates to an alternator for a vehicle which has a water pump integrally combined therewith.
2. Description of the Related Art
Recently, an increased number of electric devices and components have been installed in the vehicle and the alternator for the vehicle has been required to generate more electric power with a limited volume thereof. In addition, since the engine power has been increased, temperature in the engine compartment has become higher. As a result, it is difficult to cool the alternator by air in the engine compartment.
It has been proposed that outside air is taken from a portion under the engine to cool the alternator through a duct. In this case, however, installation of the air duct is troublesome and increases installation cost because the space of the engine compartment for the installation is very limited.
U.S. Pat. No. 4,980,588 (which corresponds to JA-A-62-189942) proposes that the engine cooling water is taken from the engine into the alternator through a water duct to cool the rectifier and the stator. In this case, the water duct becomes too heavy to the alternator having a regular size, or otherwise, the alternator size must be increased with the result of increase in weight and cost.
U.S. Pat. No. 4,922,148 (which corresponds to JA-A-1-274640) proposes that a specific cooling water passage is formed in a portion of the engine block, to which the alternator is directly fixed to introduce the cooling water into the inside of the alternator. In this case, the specific water passage in the engine block increases cost of the engine, and the water sealing in the alternator also increases the alternator cost.